The Anesthetic Effect of Anterior Middle Superior Alveolar Technique (AMSA)

Patient discomfort and intensity of intraseptal anesthesia of computer-controlled articaine/epinephrine delivery for scaling and root planing

OBJECTIVES

The primary aim was to assess the pain during intraseptal anesthesia (ISA) administration, as well as during and after scaling and root planing (SRP). The secondary aims pertained to comparing the pain in different jaw regions and evaluating the factors affecting pain during ISA administration, during and after SRP.

MATERIAL AND METHODS

ISA was obtained with three different doses of 4% articaine with 1:100,000 epinephrine (4%Ar + Ep) in 360 patients. The pain levels were measured using the visual analogue scales (VAS) for pain intensity during ISA administration (VASa), during SRP (VASi), and after SRP (VASp). These findings were then correlated with periodontal parameters. Regression analysis was performed for pain during ISA, during and after SRP.

RESULTS

Anesthesia administration was painful in 80.8% of cases. VASa negatively correlated with pocket depth (PPD). VASi showed no dose-dependency, except in mandibular premolars. VASi negatively correlated with the clinical attachment level (CAL). VASp positively correlated with PPD and CAL. Positive bleeding on probing reduced the chance of pain during ISA administration. Longer anesthesia duration and wider anesthetic field (orally) increased the prospects of painless SRP.

CONCLUSIONS

No dose-dependent differences were found regarding patient discomfort and pain intensity of ISA delivery of 4%Ar + Ep for SRP.

CLINICAL RELEVANCE

The pain during ISA administration was mild and well tolerated regardless of the anesthetic dose. A lower intensity of pain during SRP can be expected in patients with greater CAL. Post-treatment pain can be anticipated after SRP in the regions with greater PPD and CAL.

CLINICAL TRIALS REGISTRATION NUMBER

NCT04392804 (May 9th, 2020).

Efficacy of intraseptal anesthesia obtained by computer-controlled articaine with epinephrine delivery in scaling and root planing

OBJECTIVES

The primary aim of this study was to compare the anesthetic efficacy of the intraseptal anesthesia (ISA) obtained with three doses of 4% articaine with 1:100,000 epinephrine (4%Ar + Ep) for scaling and root planing (SRP), using a computer-controlled local anesthetic delivery system (CCLADS). The secondary aims were to compare the clinical anesthetic parameters in relation to different jaw regions and examine the possible influence of sex and smoking habits on them.

MATERIALS AND METHODS

SRP under ISA obtained with different doses (0.1 ml, 0.2 ml, and 0.3 ml) of 4%Ar + Ep was performed in 360 patients. The success rate, onset, duration of soft tissue anesthesia, and the anesthetic field widths were recorded by pinprick testing.

RESULTS

The anesthesia success was high (90-95%). The onset was immediate. The duration and anesthetic field widths showed a dose-related significance, however, without a consistent sex-related or smoking-related significance. The multiple logistic regression analysis revealed a twofold higher chance of anesthesia success by increasing the dose and increased bleeding on probing-related and female sex-reduced probability of anesthesia success.

CONCLUSIONS

ISA obtained with 0.3 ml of 4%Ar + Ep delivered by a computer-controlled local anesthetic delivery system provided a high anesthetic success and the adequate clinical anesthetic parameters for SRP in all regions of both jaws.

CLINICAL RELEVANCE

ISA obtained with 4%Ar + Ep provides an effective anesthesia for SRP. The anesthetic success rate may be reduced in the presence of gingival inflammation and in females as well. The study was registered in a Clinical Trials database (NCT04392804, registration date May 9, 2020).

Current status of the anterior middle superior alveolar anesthetic injection for periodontal procedures in the maxilla

Periodontal procedures require adequate anesthesia not only to ensure the patient's comfort but also to enhance the operator's performance and minimize chair time. In the maxilla, anesthesia is often achieved using highly traumatic nerve blocks, apart from multiple local infiltrations through the buccal vestibule. In recent years, anterior middle superior alveolar (AMSA) field block has been claimed to be a less traumatic alternative to several of these conventional injections, and it has many other advantages. This critical review of the existing literature aimed to discuss the rationale, mechanism, effectiveness, extent, and duration of AMSA injections for periodontal surgical and non-surgical procedures in the maxilla. It also focused on future prospects, particularly in relation to computer-controlled local anesthetic delivery systems, which aim to achieve the goal of pain-free anesthesia. A literature search of different databases was performed to retrieve relevant articles related to AMSA injections. After analyzing the existing data, it can be concluded that this anesthetic technique may be used as a predictable method of effective palatal anesthesia with adequate duration for different periodontal procedures. It has additional advantages of being less traumatic, requiring lesser amounts of local anesthetics and vasoconstrictors, as well as achieving good hemostasis. However, its effect on the buccal periodontium appears highly unpredictable.

Effectiveness of anterior middle superior alveolar injection using a computer-controlled local anesthetic delivery system for maxillary periodontal flap surgery

Background

Profound anesthesia with adequate duration is required in periodontal flap surgery, which involves the manipulation of both hard and soft tissues. The anterior middle superior alveolar (AMSA) injection may be an alternative to multiple injections required for this purpose in the maxilla. The present study aimed to assess the effectiveness of AMSA injection using computer-controlled local anesthetic delivery (CCLAD) system to anesthetize buccal hard tissue (BHT), buccal soft tissue (BST), palatal hard tissue (PHT), and palatal soft tissue (PST) around the maxillary teeth.

Methods

Thirty-five patients who were indicated for open flap debridement in a whole maxillary quadrant were given AMSA injection using the CCLAD. The effectiveness of anesthesia was evaluated using subjective and objective parameters around each tooth. Supraperiosteal infiltrations were administered to complete the surgery wherever the AMSA injection was ineffective.

Results

The AMSA injection was more effective on the palatal tissues than on the buccal tissues, as 94.14% of PST and 87.89% of PHT sites were anesthetized compared to 49.22% and 43.75% of BHT and BST sites, respectively. There was no significant difference in the frequency of anesthesia around the anterior and posterior teeth. The PHT was significantly more anesthetized (P = 0.003) in males than in females.

Conclusions

The AMSA injection using CCLAD is highly effective on palatal tissues and could be used as a first-line anesthesia for periodontal flap surgery. However, its effect on buccal tissues is less predictable, with supraperiosteal infiltration often required to supplement the AMSA injection.

Nutrient canals and porosity of the bony palate: A basis for the biological plausibility of the anterior middle superior alveolar nerve block

BACKGROUND

The authors investigated morphologic parameters of the palatal cortex that affect the diffusion of local anesthetic solution in the region of the anterior middle superior alveolar (AMSA) nerve block injection site.

METHODS

The authors used computed tomographic (CT) and micro-CT imaging to assess 20 human skulls from an anatomic collection. Analysis of the CT images included frequency, distribution, and width of the nutrient canals in the bony palate, according to to the person's sex and age. Micro-CT analysis involved measuring the thickness and porosity of palatal cortical bone in the area of the AMSA injection site in relation to the thickness and porosity of the opposite buccal cortical bone.

RESULTS

There was a statistically significant difference (P = .042) in the location of the nutrient canals between male specimens (> 50% in the border region) and female specimens (> 50% in the palatal process). Furthermore, the female skulls had significantly wider nutrient canal foramina (P = .042) than did the male skulls. Despite greater thickness, the palatal cortex in the area of the AMSA injection site had slightly greater porosity than did the buccal cortex. A significantly greater number of microcanals penetrated the whole cortical thickness in palatal than in buccal cortical bone (P = .001).

CONCLUSIONS

The distribution and width of nutrient canals differed between male and female skulls. At the microscopic level, structural characteristics of the palatal cortex provide a good anatomic basis for the potential of a satisfactory AMSA injection success rate.

PRACTICAL IMPLICATIONS

The AMSA technique success rate might be increased if the clinician adjusts the injection site to the distribution of nutrient canals, depending on the sex of the patient.

Palatal Injection does not Block the Superior Alveolar Nerve Trunks: Correcting an Error Regarding the Innervation of the Maxillary Teeth

The superior alveolar nerves course lateral to the maxillary sinus and the greater palatine nerve travels through the hard palate. This difficult three-dimensional anatomy has led some dentists and oral surgeons to a critical misunderstanding in developing the anterior and middle superior alveolar (AMSA) nerve block and the palatal approach anterior superior alveolar (P-ASA) nerve block. In this review, the anatomy of the posterior, middle and anterior superior alveolar nerves, greater palatine nerve, and nasopalatine nerve are revisited in order to clarify the anatomy of these blocks so that the perpetuated anatomical misunderstanding is rectified. We conclude that the AMSA and P-ASA nerve blockades, as currently described, are not based on accurate anatomy.